To be fair, I've always thought that distinction between whether a life form is fair game or not depending on if it has a nervous system (no more than a system of organic wires running on electricity) fairly arbitrary.

That doesn't mean I'm defending the rights of plants, merely that I think that we should be allowed to perform horrible gene splicing experiments on humans too.

I love the Deep Thoughts quote they cited on the comment thread. So beautifully elegant in this case:

"If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason."

In any case, though, I think one of the commenters had the basic motive right: "basically they are trying to limit the ability of companies like Monsanto to produce and sell you seeds whose plants will not produce seeds of their own thus forcing you to buy new seeds from Monsanto every year."

Of course, any over-arching regulation like this which intends to limit some specific entity (which would be unconstitutional) tends to be entirely misappropriated by special interest groups and otherwise insane.

(Q.v. DMCA -- intended to stop software piracy, now is being used by RIAA and MPAA to put gag orders on anyone who works in data decryption.)